Gas-muffle.



J. A. Hmmm@ GAS MUFPLB. v

` APPLICATION FILED JULY 28, 1909. l Patented Apr.1,1m3.

5 SHEETS-SHEET 2.

J. A. HBRRIGK.

GAS MUPPLE.

APPLIGATION FILED JULY 28, 1909.

Patented Apr. 1, 1913.

5 SHEETS-SHEET 3.

m -www @Vi/immo@ J. A. HERRICK.

GAS MUIPLE.

APPLIGATION FILED JULY 28, 1909.

Ll, Patented Apr.1,1913.

5 SHEETS-SHEET 4.

Fig; 4-

J. A. HERRICK.'

GAS MUPPLE. APYLIOATLON' FILED JULY 28, 1909.

Lf. l Patented Apr. 1, 1913.

5 SHEETS-SHEET 5',

Figi 6- features V of construction, combinations of UNITED sTATEs PATENToEEIcE.

JAMES A. HERRICK, OF NEW YORK, N. Y.

GAS-MUFFLE.

To all whom t may concern Be it known that I, JAMEsA. HERRiCiL residingat New York city, in the county'otl New York and State of New York, have1nvented certain new and useful Improvements in Gas-Mutlles, of whichthe following is a specification.

This invention relates, to improvements in that class'of furnaces-knownas muffles, and one of the objects there9f is to provide new andimproved apparatus of the above character designed jto provide 1ncreasedheat eiiilciency, and economy in fuel consumption.

' Another object of the invention is to provide apparatus employinggaseous fuel of such construction as will provide for uniform heatwithin the muftle.

Another object is to provide apparatus of this character which will takeup a greater quantity of the heat generated bythe burning gases than hasbeen done in similar apparatus and which will absorb, for purposes ofregeneration, a greater quantity of the heat present in the products ofcombustion.

Other objects will be in part obvious and in part pointed outhereinafter.'

The invention accordingly consists in the elements and arrangement ofparts, which will be exemplified in the constructionhercinafterdescribed, and the scope of the application of which will be indicatedin the following claims. y

In the accompanying drawings wherein is illustrated several of variouspossible embodiments of the invention: Figure'l is a vertical, sectionalview taken through the center of the preferred embodiment of my improvedmuiie; Fig. 2 is al horizontal sectional view taken substantially on theline 2 2 of Fig. 1; Fig. 3 is a similar view taken partly on the line 33 of Fig. 1 and partly o-n line 4-4 ofFig. 1; Fig. 4 is a vertical-sectional view taken substantially Aon line 4 4of Fig. 3; Fig. 5 is avertical sectional view of a different embodiment of the invention; Fig.6 isa vertical sectional view on line 6 6 of Fig. 5 in the direction ofthe arrow. p

Similar reference characters refer to similar parts throughout thevarious figures of the drawings. v

Referring now to the drawinofs, and particularly to the embodimentillustrated lin Specication of Letters Patent.

Patented Apr. 1, 1913.

Application led July 28, 1909. Serial No. 510,094.

Figs. 1 to f1 inclusive 1 indicates air passage ways which extendlengthwise of the apparatus and 2 is an air regenerative chamber whichis preferably filled with spaced blocks or checkers 3, asv shown. 4indicates gas passage ways which extend lengthwise of lthe apparatus and5 isa gas regenerative chamber which is also filled with checkers 6.

7 indicates air passage ways similar to those shown at 1 above which isarrangedl an air regenerative chamber 8 containing checkers 10. Gas,passage ways 40 similar to those shown at 4 are adapted to deliver gasto the gas regenerative chamber 11 which is also lilled with checkers12. Chambers 2 and 5 constitute one pair of air and gas regenerativechambers, and chambers 8 and 11 constitute a second pair of air and gasregenerative chambers.

Inasmuch as the apparatus now to be describedis duplex but one sidethereof may be'specifically described in orderto impart a clearunderstanding of the invention. The air after passing thro-ughthe-regenerative chamber 2 is discharged through a portfl shown indotted lines. (a similar po-rt 14 being shown in full lines leading fromchamber 8,) and flues 15 to a combustion or firing chamber 16 whichextends underneath a muiie 17. The gas from the chamber 5 is dischargedthrough the port 18 chamber 21 which extends longitudinallyof the secondmuiiie 22. Muflie 17 which eX- tends longitudinally of the apparatus isprovided with an arched Hoor 23 and an arched dome 24 above which, andspaced therefrom is a wall 25, the space provided between the muiie andthe inner surface of said wall constituting a flame space 26.

Spaced blocks or kickers 27 may be interposed between the mutlie and theinner surface of wall 25, as shown, such construction aiding in holdingthe walls of the mufles in place andproviding for a free passage way forthe Haine. These blocks 27 are arranged in the form of independentvhorizontally spaced piers 27', which extend upwardly to the spring lofthe mutlie arch, and divide the ame space into a series of spacesI I ofopenwork construction, for viewing and Ventilating purposes, and toallowA of expansion. The reason for graduating the size of the spacesbetween piers is in order that more flamemay be directed toward the doorend of the Inutile, where the spaces are largest, than to the back end,where the s aces are smaller. Ports as at 28 are pro-- vided betweenchamber 16 and the Hama space 26 through which dames may pass about themuiile. v

Arranged midway between mutlles 17 and '22 isv a. wall 30, said wallcomprising a plurality of alternately arranged U-shaped portions 31 and32 clearly shown in Fig. 2 of the drawings, the construction being suchthat alternate U-shaped portions '31 and 32 are disposed respectivelybeneath the dame spaces 26 and 33 of muflies 17 and ,22. 1t

Awill be seen that 'this construction not only permits the passage ofHaine from one flame space to the other but also permits the directpassage of liames from the combustion chamber 16 of mutlle 17 to theflame space 33 of mulile 22 and vice versa. 1f desired, small openingsas at 34 may be provided in this wall to permit of the passage of asmall quantity of the fiame directly from one combustion chamber to theother. e

Referring now to Fig. 4 of the drawings 35 indicates a Vconduit adaptedto deliver gas to the apparatus and 36 indicates a similar conduitthrough which air may be delivered; the'passage of the gas and airthrough said conduits being controlled as by means of valves 37 and 38.The conduit 37 communicates with the gas passage ways 4 and 40respectively which extend underneath the gas regenerative chambersaround either side of the 'apparatus and the air conduit 36 similarlycommunicates with'the air passage ways 1 and 7. The direction of flow ofgas and air may be controlled 4as by means of valves 41 and 42 shown inFig. 4. These valves are adaptedto deflect the gas and air to one sideof the apparatus to the exclusion of the other, and at the same timeopen the air and gas passage ways upon the side of the apparatus fromwhich the air and y gas is excluded, to a flue 43 which leads to Y astack 44.t 1t will be seen therefore that when gas and air enter throughone side of the apparatus the lopposite side thereof is Vopen to the Hueand stack so that the prod ucts of combustion may be dischargedtherethrough as will be hereinafter more fully eX- plained.' A valve asat 45 may be provide in due 4,3.

Las by means of the t meanest Having thus described the construction ofthis embodiment of my invention the operation thereof may now beunderstood.' 'llhe valves 41 and 42 being properly positioned, the gasand air pass through .the passage ways 4 and 1 to the regenerativechambers 5 and 2l and then pass upward through said regenerativechambers between. checkers 6 and 3 which will be heated, as will behereinafter described and which will giveup a part lof said heat to saidingoing gas and air; The gas and air will then be delivered ports 18 and13 and tlues`20 and115 to the combustion chamber 16, through theapertured partition 100 whichseparates the regenerative chambersfromythe combustion chambers. The gas and air mixing at this point,burst'into flame just above ports or lues 20 and 15, and at this point,it may be noted that these flues have a greater cross-sectional area atthe front or door end of the mutlie, than at the rear and decreaseregularly in 'crosse vsectional area from front to rear of theapparatus.I IThis construction provides for a greater amount of flame atthe front part of the apparatus. The ports 28 which lead from thecombustion chamber 16 to the llame space 26 are `similarly constructedso that a greater portion of the `flame will pass about the front end ofthe mulile. This lconstruction is desirable for the reason that, owingto the fact that the` front or. door of the inutile is opened frequentlyfor the insertion andremoval of the material to be treated,

it is necessary t-ol supply a greater amount of heat through the frontportion of the mutlle. For the same reason the flame space 26 ispreferably of greater cross-sectional area at the front end of themulile than it is at the rear end; and the openings in the checker-workare also preferably somewhat larger at the front end than at' the Lrearend of the'air and gas generative chambers.

The flame in the combustion chamber 16 divides, one part passing to theoutside through ports 28 around the lower corner of the mulle up thesideand' over the top thereof, fillingy the entire/space between the sameand the surface of the outside walls. This flame passes entirely aroundthe first muftlc from' left to right, and then drops down through/thedues 46 formed by the 'Ll-shaped portions 31 and '32 ofjwall' 30intochamber 21, which, when the flame is passing in this direction throughthe apparatus, may be termed a gathering chamber. The other part of thellames pass between the legs'of the U-shaped members thence through dues47 and upward about the second muihe 22 whence they return through ports48 to the chamber 21. From chamber 21 the dames pass down thrugh thedues 50 and ports 14 and 51 into the regenerative chambers 8 and 11whence they pass through the passage scribed by means of the valves 41and 42v which deflect same throu h the passage ways upon the oppositeside o? the apparatus.

Suitable blocks as at 52 and 53 may be slidably mounted in lateralopenings provided in walls 25 and 54. These blocks may be slid in andout to vary the size ofthe passage ways 28 and 48 throughpwhich theflames pass from the combustion 'chambers to the flame spaces about themuies, in order that the amount of flame required to properly heat anyportion of the muile may be regulated.

When the apparatus has been in operation for some time the rear portionof the muiiie will be very much, hotter than the front portion, onaccount of the door`and the pull of the stack. In order to relieve thiscondition I may provide valve-controlled openings in the rear wall ofthe apparatus, so that communication may be established lbetween thcatmosphere and the fiame chamber and also between atmosphere and theinterior of the muie, when desired. p

Referring to the embodiment of my invention shown in Figs. 5 and 6 ofthe drawing, 55 denotes a gas regenerative chamber and 56 an airregenerative chamber corresponding chambers 57 and 58 being providedupo-n the right hand side of the apparatus. Air and gas are delivered tothe regenerative chambers and 56 as by means of passage waysY 60 and 61;similar passage ways 62 and 63 being provided to deliver gas to theother side of the apparatus. Suitable valve mechanism (not shown) isprovided for delivering air and gas to regenerative chambers at one sideof the apparatusand for allowing the products of combustion to pass tothe stack; the direction of flow of the gas through the apparatus beingdetermined by the` position of the valves. Mounted above theregenerative chambers is the muiile 64 having the arched floor 65 and 55the arched dome 66 about which is positioned an exterior permanent wall67 leaving a space 68 between the muflle and wall which provides a'flame space. Suitably spaced bricks or kickers are employed forsupporting the lateral walls of the muiile. Extending longitudinallyunderneath mufile 64 is a palr'of chambers 70 and 71 respectively,separted by a wall 72 which, if deslred, may be provided with aperturesas shown in dotted lines. Passage ways 73 and 74 lead from regenerativevchambers 55 and v56 to chamber 70 and similar passage ways 59 and 69lead from the regenerative chambers 57 and 5 8 to chamber 71. The seriesof mouths of the two series of passage ways upon two sides of theapparatus which lead from the regenerative chambers to the chambers 7 Oand 71 are preferably arranged in alternation. 72 and 731 are`auxiliarygas conduits leading direct from the gas regenerative chamberto the flame space 68. Leading from chamg bers 70 and 71 to the flame'space 68 are lateral passage ways 7 fl and 7 5', said passage waysallowing flame to pass upward about the dome of the muflie to the flamespace 68. The exterior wall of the apparatus may be providedwith'suitable apertures at any desired point in which may be'mountedslidable'blocks as at 76. These blocks when slid inwardly or outwardlyare adapted for vary-l ing the size of the various flues. In theoperation of this embodiment of my invention the gas and air passingupward through the regenerative chambers 55 and 56 mix in the chamber 70'where they' are ignited. The flame then passes through passage way 74,thence upward about the dome lcf the mufile through the flame space 68,then downward about the mutlie, partl thereof then passing throughpassage way 59 into the chamber 57, and part thereof passing downwardthrough the passage way 69 into the gas regenerative chamber 58. Thus itwill be seen that some of the flame entering chamber 57 may passdownward into air regenerative chamber 58 and some through passage Ways59y and 73l into the gas regenerative chamber 57. These chambers, as inthe first above described embodiment, are filled with 'checkers' 77which-operate to absorb the heat present in the products of combustion,so that when the direction of flow of air and gas through the apparatusis reversed such heat will be used in preheating such gas and air, thedis-v charging products of combustion operating to replenish the heat inthe checkers located in the other pair of regenerative chambers. It willbe obvious that some of thegas will pass upward through either of thetubes 7 3 to meet thc fiame passing through the lateral openings 74 and75 which lead from the' chambers 70 and 71 to the flame space 68. Forrelieving an overheated condition of the back of the mulile, I mayprovide suitable valve-controlled passages in the back wall of theapparatus, as indicated at 68', whereby communication may be establishedbetween the back of the flame space 68 and atmosphere. And similarly, tocool the `back of the muffle itself when desired, I may provide similarpassages 64', to establishcommunication between the back of the mufiieand atmosphere.

Accordinglyit will be seen that I have. provided constructions welladapted among others to maintain all the ends and objects pointed out inan entirely simple yet ecient manner.

. The various regenerative' chambers and the passage Ways leadingtherefrom to the chambers underneath the mutlles and the yflame spaceswhich surround them are vso arter contained in the rabove descriptionorv shown in the accompanying drawings shall be interpreted asillustrative and not in al limiting sense. It is also tobe understoodthat the language used in the following claims is intended to cover allof the generic and specific features of the invention herein describedand all statements of the scope of the invention, which as a matter' oflanguage, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secureby Letters Patent is: 4

1. In apparatus of the class described, a muHle having asurrou'ndingflame-space, a combustion chamber communicating with said flame space,regenerative .chambers communicating with said combustion chamber fordelivering heated air and gas thereto, and an apertured rpartitionbetween said regenerative chambers and the combustion chamber.

2'. In apparatus of the class described, a pair of muies, a wall abouteachv of said mufles and spaced therefrom, a chamber underneath each ofsaid muliles, a wall separating said chambers and provided With iamepassage Ways, and a pair of regenerative chambers located beneath eachof said first mentioned chambers.

3. In apparatus ofthe class described, a pair of inutiles, a Wall abouteach of said mutiles and spaced therefrom, a chamber' underneath each ofsaid muffies, a Wall separating said mufliesand provided, with flamepassage Ways, an air and a gas regenerativev chamber yarranged beneatheach of said first mentioned chambers, and partitions provided with gasand air passage ways posi-l tioned between said 'regenerative chambersand said irst mentioned chambers.y

4. In apparatus of the class described, a

pair of mufiles, a wall about each of said muffles and spaced therefrom,a chamber underneath each of said muflies, a wall sepai rating saidchambers, said wall providing passage ways from the space surroundingone mufe to that surrounding the other, an

an air and a gas regenerative chamber arranged beneath each of saidchambers, each noevgeaa of said. last mentioned chambers being providedwith a series of ports, the ports of the two series being tion.

l5. In apparatus of the class described, a

'pair of mules, a wall positioned about each of said inutiles and spacedtherefrom, a chamber underneath each of said muiiies, a wall separatingsaid chambers, said Wall lbeing so formed as to provide passage waysbetween the spaces formed between the inutiles and said first mentionedwalls, an air and a gas regenerative chamber arranged beneath eaehofsaid first mentioned rchambers,.each of said last mentioned chambersbeing providedy with aseries of ports,

the 'ports ofsaid two series being arranged in alternate relation,A anda passage way common to said ports for conducting a mix'- ture of airand gas to said first mentioned chambers. v

6. In apparatus of the class described, a pair of mu'tfles, a Wallaboutea-ch of said inutiles and spaced therefrom, a combustion chamber'beneath each said muftles, a wall separating said chambersl and soformed as to connect the spaces formed between the same and said muiies,and a gas and an air regenerative chamber disposed beneath each of saidirstmentioned chambers.

7. In apparatus of the class described, a pair of mufdes, a' gas andanair revenerative chamber located beneath each of said mufdes, a wallprovided with as and air ports located above each of sai regenerativechambers, means for directing a dame first about one of said inuiiiesand then about the other, and means for introducing air and gas into onepair of regenerative chambers and for allo-wing the products ofcombustion to be discharged from the other air of regenerative chambers,said means being. adapted to reverse the direction of How of air and gasand the discharge of the products of combustion through said apparatus,

8. yIn apparatus of the class described, a)

arranged in alternate rela-l may pass firsthorizontally and then up- Awardly about the mules, one portion of the {lamepassing about one muiiieand the other portion thereof about theother mtime', a pair ofregenerative chambers for delivering a` mixture of gas and air to one'of said chambers, anda second' pair of chambers through which productsofcombustion may pass.

9. In apparatus of the classl described, a

pairofgas fired muffles, eachv of which is provided with a combustionchamber below the same, Walls surrounding said mutiies and spacedtherefrom to rov-lde flame spaces. flues connecting the said chambers,iues connecting the spaces. above the muifles, means for introducing amixture of gas and air into one of said chambers and for Withdrawing theproducts of combustion from the other of said chambers, means forcausing the flame to divide so that part thereof will pass about onemuiile and part about the other muie, and means for reversing thedirect-ion of said flow of flame about said mufiles. v

10. In apparatus of the class described, a pair of mulfles each of whichhas a surrounding flame space and a firing or collecting chamberdisposed beneath the same, a pair of chambers arranged below each ofsaid first mentioned chambers, one pair of said last mentioned chambersbeing adapted to deliver a mixture of gas and air to one of said rstmentioned chambers and the other pair of said mentioned chambers beingadapted to receive the roducts of com bustion from the other o saidfirst mentioned chambers and to store the heat remaining in saidproducts of combustion.

11. In apparatus of the class described, a pair of -mullles each ofwhich is provided -With a combustion chamber beneath the same and a.surrounding flame space, passage Ways connecting said flame spaces,passage Ways connecting said chambers, a pair of chambers disposedbeneath each of said first mentioned chambers and connected therewith bymeans of passage Ways, each pair of last mentioned chambers comprising agas regenerative chamber and an air regenerative chamber, means forintroducing air and gas into one pair of said last mentioned chambers,and means whereby passage of gas, air and products of combustion throughsaid apparat-us may be reversed, each pair of said last mentionedchambers being provided with means for absorbing heat present in theproducts of combustion and for delivering said heat to the ingoing gasand air.

l2. In apparatus of the class described, a mufile, a .Wall positionedabout the same to provide a flame space, a chamber underneath saidmufile and extending the entire length thereof, an air regenerativechamber located beneath said muffle, a gas regenerative chamber locatedbeneath said muie, each of said last mentioned chambers being providedWith a series of fiues and the fiues of said series being arranged inalternate relation, and a series of flues terminating in the bottom ofsaid first mentioned chamber which connects the same with the fluesleading from the air and gas regenerative chambers.

13. In apparatus of the class described, a muffle, a wall about saidmuffle and spaced therefrom providing a flame space, blocks interposedbetween said mufile and said wall, a chamber arranged beneath saidmulile and extending longitudinally thereof,

passage ways connecting said chamber with said flame space, a gas and anair regenerative chamber located beneath said muffle, each ofv saidchambers having a series of ports leading therefrom to said first men-`tioned chamber, said ports being arranged in alternate relation.

14:. In apparatus of the class described, a pair of muifles each ofwhich is provided vwith a surrounding flame space, passage waysconnecting said llame spaces, a chambar arranged underneath each of saidmuflies and extending longitudinally thereof, a pair of chambers'arranged beneath each of said first mentioned chambers, one chamber ofeach of said first mentioned pair of chambers comprising -a gasregenerativel chamber and the other chamber of eachpair an airregenerative chamber, alternately arranged .passage Ways connecting thechambers of each pair to one of said first mentioned chambers, and meanswhereby gas and air may be introduced into said apparatus through onepair of regenerative-chambers and the products of combustion dischargedthrough the other pair thereof.

15. In apparatus of the class described, a pair of mufiies each of whichis provided with a surrounding flame space, passage Ways connecting saidflame space, a chamber arranged underneath each of said mufles andextending longitudinally thereof, a pair of chambers arranged beneatheach of said rst mentioned chambers, one chamber of each of said firstmentioned pair of chambers comprising a gas regenerative chamber and theother chamber of each pair an air regenerative chamber, alternatelyarranged passage Ways connecting the chambers of each pair to one ofsaid first mentioned chambers, means whereby gas and air may beintroduced into said apparatus through one pair of regenerative chambersand the products of combustion discharged through the other pairthereof, and means in each of said last mentioned chambers for absorbingthe heat presentv in the products ofcombustion.

16. In apparatus of the class described, a pair of mutlles, each ofwhich is provided with a surrounding flame space and a lon'gi`tudinally' extending combustion chamber arranged beneath t-he same,passage ways connecting-the flame space of each of said muiiles and forconnecting the combustion chamber of each mufile with its flame space, apair of regenerative chambers located beneath each of said mufiles,means whereby al mixture of gas and ain may be introduced into theapparatus through one pair ofregenerative chambers and the products ofcombustion discharged through the other thereof, means in each of saidregenerative chambers for absorbin the heatvpresent in the products ofcomustion, and means whereby the direction of ow of gas and air and thedischarging of the products of combustion througlrthe Asame apparatusmay be reversed.

- 17. In apparatus ofthe class described, a inutile provided with asurrounding flame space, a chamber arranged underneath said mulile andextending longitudinally thereof, passage ways connecting said chamberwith said flame space, said passage ways uniformly decreasing incross-sectional area from the front to the rear of the inutile, gas andair regenerative chambers arranged underneath said first mentionedchamber, and passage ways connecting saidn-egenerative chambers withsaid first mentioned chambers, said passage ways uniformly decreasing incross-sectional area from the frontto the rearof said mufl'le.

18. In apparatus of the class described, a muffle provided with asurrounding flame space and having a longitudinally extending combustionor liringchamber arranged beneath the same, a series of passage waysconnecting said chamber with said flame space, said passage waysincreasing in cross- Sectional area from the rear to the front of themulile, a pair of regenerative chambers arranged underneath saidInutile, each chamber being connected with said lirst mentioned chamberby a series of passage ways Which are arranged in alternation and whichdecrease in cross-sectional area from the front to the rear of theapparatus, and means in each of said last mentioned chambers foryabsorbing heat from the products of combustion and for givingotf saidheat to the f ingoing gas or air.

19. In apparatus of the kind described, a Inutile, and a wall positionedabout the same to provide a flame space Substantially coextensive withthe mutle, the cross-sectional area of the flame space being greater atone end than at the other.

20. In apparatus 'of the class described, a muflle, a wall positionedabout the same to provide a flame space substantially co-extensive withthe Inutile, the cross-sectional area of the flame space being greaterat one end than at the other, a combustion chamber below the mulile andopening into the flame space, and a chamber opening into said combustionchamber by way of a row of ports, the port at one end of the row beinglarger than the port at the other end.

2l. In apparatus of the class described, a muflle, a wall positionedabout the same to provide a fla-me space substantially co-extensive withthe muffle, the cross-sectional area of the llame space being greater atone end than at the other, a combustion chamber below themuliie andopening into the flame space, and a chamber opening into said comabustion chamber by Way of a row of ports,

romena thel port at one end of the row being largerY than the port atthe other end, said last named chamber being filled with checkerwork,the openingsr whereof at one end of the chamber are larger than those atthe other end.

22. In apparatus of the kind described, a longitudinally extendingmuffle having a surrounding flame space and a longitudinally extendingcombustion chamber beneath and in alinement therewith, a row ofpassageways along the length of the combustion chamber and connectingthe same with the flame space, and means for varying the size of eachone of said row of passageways, whereby the amount of flame required toproperly heat any portion of the mufl'le may be regulated.

23. In apparatus of the kind described, a. closed inutile having asurrounding wall spaced therefrom to provide "a flame-space about themulile and extending from front to rear thereof, there being a valvedopening connecting the rear of the flame-space with the outer air.

24. In apparatus of the kind described, a closed Inutile having asurrounding Wall spaced therefrom to provide a llame space about themuflle=and extending from front to rear thereof, there being a valvedopening in the rear wall of the inutile to the outer air.

25. In apparatus of the kind described, a closed mulile having asurrounding wall spaced therefrom to provide a flame space transverselyabout the mulfle and extending from frontl to rear thereof, the rear endof the flame space being defined by a Wall which is an extension of therear wall of the Inutile, said wall having a valve-controlled openinginto the rear of the flame I a mulile having an arched top, a wallpositioned about the muffle tol rovide a flame space, and independenthorizontally spaced piers between the mulile and the surrounding wall,each pier extendingsubstantially up to the spring of the muflle archwhereby vertically unobstructed passages are formed between adjacentpiers.

27. In apparatus of the kind described, a Inutile having an arched top,a Wall positioned about the Inutile to rovide a llame space, andindependent horizontally spaced piers between the muflle and thesurrounding Wall, each pier extending substantially up to the spring ofthe mufile arch whereby vertically unobstructed passages are formedbetween adjacent piers, said piers being of openwork construction.

28. In apparatus of the kind described, a mulile having an arched top, awall ositioned about the muile to provide av ame space, and horizontallyspaced iers between the mule and the surroun ing wall, each pierextending substantially up to the spring of the inuflle arch, said piersprovid:

. ing graduated-f spaces between them from` end to end of the inutile.

2S). ln apparatus of the kind described, a muflie having an arched top,a. wall positioned about the muffle to provide a flame space, andindependent horizontally spaced piers ybetween the muflle and thesurrounding wall, each pier extending substantially up to the spring ofthe inutile arch whereby vertically unobstructed passages are formedbetween adjacent piers, there being a flame port into the space betweeneach pair of piers.

30. In apparatus of the kind described, a mutiie having an arched top, awall positioned about the muflic to provide a iame space, andhorizontally spaced iers be tween the maille and the surroun ing-Wall,each pier extending substantially up to the spring of the mutlle arch,there being a flame port into the space between each pair of piers, saidflame ports being graduated as to size from end to end of the mutfle.

3l. In apparatus of the class described, a Inutile structure having asurrounding flame-space, a plurality of combustion chamberscommunicating with said flamespace at diii'erent points, a regenerativechamber for each ofsaid combustion chambers, and an apertured partitionbetween each regenerative chamber and the corresponding combustionchamber.

82. In apparatus of the class described, a Inuttle having a surroundingnamespace,

ka combustion chamber communicating With said flame-space, aregenerative chamber communicating with said combustion chamber, and anapertured partition between Said regenerative chamber and the combustionchamber.

In testimony whereof I aiiix my signature in the presence of twoWitnesses.

JAMES A. HERRICK. Witnesses:

ADELE Homcsrsmc, BLANCHE WV. CoULDocK.

